Negative electrode, electrochemical device and electronic device

Abstract

A negative electrode comprises a negative electrode current collector, a first active material layer, and a second active material layer; wherein the second active material layer is located between the negative electrode current collector and the first active material layer; the first active material layer comprises a first active material and a target compound, the target compound comprises AxBy, where 0<x≤4, 0<y≤8, A comprises a metal element comprising at least one of the group consisting of Li, Na, Mg, Ca, Zn, and Cs, and B comprises a non-metallic element comprising at least one of the group consisting of N, S, and Si.

What is claimed is: 
     
         1 . A negative electrode, comprising:
 a negative electrode current collector, a first active material layer, and a second active material layer;   
       wherein
 the second active material layer is located between the negative electrode current collector and the first active material layer; 
 the first active material layer comprises a first active material and a target compound, the target compound comprising A x B y , wherein
   0 <x≤ 4, 0 <y≤ 8; 
 A comprises a metal element comprising at least one selected from the group consisting of Li, Na, Mg, Ca, Zn, and Cs; and 
 B comprises a non-metallic element comprising at least one selected from the group consisting of N, S, and Si. 
 
 
     
     
         2 . The negative electrode of  claim 1 , wherein A x B y  is at least one selected from the group consisting of Li 3 N, Li 2 S, Na 3 N, Na 2 S, Ca 3 N 2 , CaS, Mg 3 N 2 , and MgS. 
     
     
         3 . The negative electrode of  claim 1 , wherein the target compound has a mass percentage of 0.1% to 20%, based on a total mass of the first active material layer and the second active material layer. 
     
     
         4 . The negative electrode of  claim 1 , wherein the first active material layer has a thickness of h1, and the second active material layer has a thickness of h2, and wherein
 10%≤ h 1/( h 1 +h 2)≤90%.   
     
     
         5 . The negative electrode of  claim 4 , wherein 10%≤h1/(h1+h2)≤50%. 
     
     
         6 . The negative electrode of  claim 1 , wherein,
 the first active material has a capacity per gram of c1;   the first active material has an average particle size of d1;   the second active material layer comprises a second active material;   the second active material has a capacity per gram of c2; and   the second active material has an average particle size of d2; and   wherein c1×d1≥c2×d2.   
     
     
         7 . The negative electrode of  claim 6 , wherein 6 μm≤c1≤20 μm. 
     
     
         8 . The negative electrode of  claim 1 , wherein the second active material layer comprises a second active material, and a capacity per gram of the first active material is greater than or equal to a capacity per gram of the second active material. 
     
     
         9 . The negative electrode of  claim 1 , wherein the second active material layer comprises a second active material; and an average particle size of the first active material is greater than or equal to an average particle size of the second active material. 
     
     
         10 . An electrochemical device, comprising:
 a positive electrode;   a negative electrode; and   a separator located between the positive electrode and the negative electrode;   
       wherein the negative electrode comprises:
 a negative electrode current collector, a first active material layer, and a second active material layer, and wherein
 the second active material layer is located between the negative electrode current collector and the first active material layer; 
 the first active material layer comprises a first active material and a target compound, the target compound comprising: A x B y , 
 wherein 0<x≤4, 0<y≤8; 
 A comprises a metal element comprising at least one selected from the group consisting of Li, Na, Mg, Ca, Zn, and Cs; and 
 B comprises a non-metallic element comprising at least one selected from the group consisting of N, S, and Si. 
 
 
     
     
         11 . The electrochemical device of  claim 10 , wherein A x B y  is at least one selected from the group consisting of Li 3 N, Li 2 S, Na 3 N, Na 2 S, Ca 3 N 2 , CaS, Mg 3 N 2 , and MgS. 
     
     
         12 . The electrochemical device of  claim 10 , wherein the target compound has a mass percentage of 0.1% to 20%, based on a total mass of the first active material layer and the second active material layer. 
     
     
         13 . The electrochemical device of  claim 10 , wherein the first active material layer has a thickness of h1, and the second active material layer has a thickness of h2, and
 10%≤h1/(h1+h2)≤90%.   
     
     
         14 . The electrochemical device of  claim 13 , wherein 10%≤h1/(h1+h2)≤50%. 
     
     
         15 . The electrochemical device of  claim 10 , wherein,
 the first active material has a capacity per gram of c1;   the first active material has an average particle size of d1;   the second active material layer comprises a second active material;   the second active material has a capacity per gram of c2; and   the second active material has an average particle size of d2; and   wherein c1×d1≥c2×d2.   
     
     
         16 . The electrochemical device of  claim 15 , wherein 6 μm≤c1≤20 μm. 
     
     
         17 . The electrochemical device of  claim 10 , wherein the second active material layer comprises a second active material, and a capacity per gram of the first active material is greater than or equal to a capacity per gram of the second active material. 
     
     
         18 . The electrochemical device of  claim 10 , wherein the second active material layer comprises a second active material; and an average particle size of the first active material is greater than or equal to an average particle size of the second active material. 
     
     
         19 . An electronic device comprising an electrochemical device comprising a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, the negative electrode comprising:
 a negative electrode current collector, a first active material layer, and a second active material layer,   
       wherein
 the second active material layer is located between the negative electrode current collector and the first active material layer; 
 the first active material layer comprises a first active material and a target compound, the target compound comprising: A x B y , 
 
       wherein
 0<x≤4, 0<y≤8, 
 A comprises a metal element comprising at least one selected from the group consisting of Li, Na, Mg, Ca, Zn, and Cs, and 
 B comprises a non-metallic element comprising at least one selected from the group consisting of N, S, and Si.